In the conventionally-known method for manufacturing a scanning lens made of plastic resin, resin is injected into a mold having a cavity corresponding to the contour of the scanning lens, and thereafter the molded product in the mold is thrust out by ejector pins. Accordingly, the scanning lens is removed from the mold. To be more specific, the scanning lens has flat surfaces parallel to the main scanning direction, and the ejector pins push these surfaces in the optical axis direction by their distal end faces (surfaces parallel to the main scanning direction), thereby removing the scanning lens from the mold.
A scanning lens may have slant surfaces slanting relative to the main scanning direction. If this scanning lens is thrust out by the conventionally-known ejector pins each having a flat distal end face parallel to the main scanning direction, the scanning lens may not be removed easily and smoothly by the ejector pins, because these ejector pins are unable to arrange at positions corresponding to the slant surfaces.
It would be desirable to provide a scanning lens such that removal of the scanning lens from a mold can be performed with increased ease.